Lost Kitty by Natasha Duncan-Drake
Anna and Neil are brother and sister, just a few years apart; as they sit one hot day they hear something land in their pool. When they go investigate, they find a cat-man, about their age.
Now they need to find a way to get him to London, get a crystal bracelet from the Egyptian display at the museum and then somehow get their friend, Lani, home. While they were being chased by government agents, of course.
This is a fun joyful little story of friendship, and ultimately family. Also, that sometimes, the government can be trusted, but you have to make them prove it. Five stars for this cute story.